(1) Field of the Invention
The present invention generally relates to a conveyor device. More particularly, the present invention relates to a conveyor device for flexible articles such as a bundle of printed matters or newspapers.
(2) Description of the Prior Art
In a printing factory numerous conveyor devices have been employed to move printed material which undergoes a stacking process, a wrapping process, a strapping process, a distributing process and so on.
For example, in a newspaper printing factory, printed and folded papers are counted and stacked in a counting and stacking device following their passage through a folding device of a printing press. The stacked papers are bundled into one sheaf. These bundled papers are forcibly transferred by a conveyor device moving at a predetermined speed and for a predetermined direction. This conveyor device is arranged at the inlet and outlet sections of several devices such as a wrapping device, a strapping device, a distributing device and so on. Thus the bundled papers are subjected to required processing and/or checked prior to bundled distribution.
FIG. 7 is a perspective view showing a typical conventional conveyor device 2. This device comprises a plurality of rollers 21, 21a arranged in parallel with each other, a plurality of top plates 4 interposed between the rollers, and a plurality of conveying members 22 in a belt, wire, or chain shape. The conveying members 22 are bridgingly extended between the rollers and the sections between them are supported by the top plates 4. When, the rollers 21a are driven by a driving mechanism in the same direction, the conveying members 22 move together in the same direction. An article laid on the conveying members 22 also moves due to the friction between the conveying members 22 and the article.
As shown in FIG. 7 and FIG. 8, in a conventional conveyor device, the conveying members 22 are so arranged as to allow a continuity of the conveyor device. In detail, one conveying member 22 is bridgingly extended between a single roller 21 and one of dual rollers 21a. The adjacent conveying member, in the vertical direction in FIG. 8, is bridged between a single roller 21 and another roller of the dual rollers 21a. Further, in the horizontal direction in FIG. 8, the conveying members 22 of the forwarding conveyor unit and that of the following conveyor unit are assembled on the identical roller represented by an arrow B in order to make a continuous conveyor line. However, a discontinuous space indicated by an arrow A in FIG. 7 is required for a strapping device to apply a strapping member around an article moving on the conveyor.
If the moving article is a flexible substance such as a bundle of newspapers, this conventional conveyor device may cause problems when the moving article is subjected to a large force (e.g., forces resulting from entanglement of loose bundling straps) other than the friction force between the article and the conveying member. Since the thickness of a bundle of newspapers is not constant, since the number of newspapers to be sent depends on each delivery station or the like, some bundles consisting of an extremely small number of newspapers have to be wrapped and delivered. Such bundles are too flexible to stretch the strapping member, so that the loose strapping member may become pendent. This pendent strapping member may be easily entangled in the roller, the conveying member, or the other elements of the conveyor device at the discontinuous space between the conveyor units, or the conveyor device and the other devices such as transfer device, distributing device, loading device, delivery device, or the like. This could cause the moving article to injure personnel, drop from the conveyor line, or in the extreme case, cause the conveyor line to stop.